When taking on the role of Elton John in musical biopic Rocketman, the singing came easily to star Taron Egerton, who actually performed “Your Song” as his audition piece for the Royal Academy of Dramatic Art. Egerton sings all of the songs in the movie, sometimes joined by his co-stars. However, he didn’t know how to play piano before being cast, which posed a challenge when playing a musician renowned for his piano skills.

Enter Michael L. Roberts, an acclaimed multi-instrumentalist who served as the vocal, piano, and performance coach on Rocketman - teaching Egerton to play some songs, and teaching him how to make it look like he was playing others. One scene where Egerton can be seen playing an entire song authentically is Elton John’s first performance at the Troubadour, a famed Los Angeles club, which becomes the stage for a gravity-defying rendition of “Crocodile Rock.” Egerton trained for weeks before production began in order to be able to nail the technical aspects of playing piano and, more importantly, really selling the performance on camera.

In the lead-up to production, Roberts worked not only with Egerton but also his younger counterparts: Matthew Illesley, who plays the youngest version of Elton John (or, as he was known then, Reggie Dwight), and Kit Connor, who plays a young adolescent version of the singer. Both had to be strong performers in their own right, with Illesley leading the movie’s opening number, “The Bitch is Back,” and Connor kicking off the complex and chaotic “Saturday Night’s Alright For Fighting.” Here’s what went into making Rocketman’s musical performances, according to Roberts.

How long did you spend working with Taron - teaching him to half play piano, half pretend to play piano?

What was the most challenging song in the film?

It worked out as about two to three hours a day, five days a week, for six to eight weeks in pre-production. And then I was there on set with him every time he was at the piano to to give reminders and help structure each scene.

Elton is very flamboyant in his style on the piano, but does he have any particular kind of tics or specialities?

I think when you when you watch it through the sheer volume of movement, things to remember, and being suspended on wires, it’s got to be “Crocodile Rock” in terms of just sheer incredible feat of performance.

What was it like working with the younger Eltons?

I think he’s fundamentally, irrespective of the of the visual element, he’s born out of very solid classical piano technique and a really deep rooted sense of blues and rhythm of blues. And so I feel that permeates everything that he plays.

Are there are any particular scenes in the film where you can watch and see that it’s Taron playing that song all the way through?

Fantastic. So the first thing with young Matt Tillesley is there’s no sense of inhibition at his age, and he was actually a very good piano player. He was putting us all to shame, day after day on the set. So my piano coaching with him was very easy, but you’ve got that boundless sense of complete lack of inhibition which means that he’s responding honestly to everything, and the joy that you see in his face and what really gives that gives you that sense of what a warm child Elton was, is so much down to his sense of boundless freedom in that regard. As far as kids are concerned he’s just this consummate professional at this incredible young stage of his life.

So if you wanted to fake being able to play the piano, how would you go about it?

Yeah. So whilst the sound that you’re hearing is is recorded afterwards, obviously, “Crocodile Rock” is pretty much entirely Taron. Everything you see him hitting is for real. And “Your Song,” “Benny and the Jets,” when he’s in the Queen costume, all of that is for real. And leading into “I’m Still Standing” at the end. Whenever you see his hand reach out, he knows he knows exactly where he was going for.

It’s a tough one, but do you have a favorite Elton John song?

Fundamentally it’s the question of the rhythm. If you’re hearing something that sounds crazy heavy blues licks, and you’re seeing someone be very small at the instrument, then obviously that’s not going to be believable in any way, shape or form. When you actually get close up on the actor at the piano then everything about the body rhythm and the hand rhythm is what will either make it look convincing or give it away in terms of someone faking it.

Rocketman is now available on 4k Ultra HD, Blu-ray, DVD and Digital.

No [laughs]. I think it’s impossible. “Candle In The Wind” resonates with me emotionally as a Welshman, from the 1997 moment in so far as the Princess Diana’s funeral. That was the first time having been so familiar with all of Elton’s works that I really felt a sense of emotional connection to it. And I think “Crocodile Rock” was the most fun on this film, and “Your Song” was the most magical to be just off the side of the set for.

More: Every Elton John Song In Rocketman